Production of stencils for use in duplicating manuscript and typewritten documents, drawings, and the like



Patented Dec. 16, 1924.

PATENT OFFICE.

ABKAND :Dll WAELE, OF LONDON, ENGLAND, ASSIGNOB TO D. GISTETNER, LIMITED,

01 LONDON,

PRODUCTION OI STENOILS FOR USE IN DUPLICATING MANUSCRIPT AND TYPE- WRIT'IEN DOCUMENTS, DRAWINGS, AND LIKE.

Ho Drawing.

To all whom it may-concern:

Be it known that I, ARMAND nnWAELn, a subject of the King of Great Britain and Ireland, and residing at 29 Belmont Ave- 5 nue, Palmers- Green, London, N. 13, England, have invented certain new and useful improvements in and relating to the production of stencils for use in duplicating manuscript and typewritten documents, drawings, and the like, of which the following 1s a specification.

This invention relates to the production of stencils for use in duplicating manuscript and typewritten documents, drawings and the like, and particularly to the type of stencil in which a porous support, such as yoshino paper, is provided with a stencil layer including on organic colloid, for instance a coagulated protein, which does not needmoistening in order to soften the coating composition prior to cutting the stencil. p a

Certain difficulties arise in the production of stencils of this kind, the main difficnlty being due to the fact that comparatively few tempering agents, the pres ence of which in the stencil layer is, generally speaking, (if not invariably) necessary, have hitherto been able to be brought into sufliciently intimate association with the colloid.

The choice of the tempering agents has therefore been limited to such as when dissolved in suitable organic solvents can be .vention the desired degree of dispersion of incorporated in the composition used for coating or can be emulsified and in the form of emulsions mixed with the solution of the main colloid constituentof the coating composition;

In some cases, however, it has been proposed to convert the tempering a cut into a water-soluble or water-emulsifiab e derivative which can be mixed with the solution of the colloid and optionally be subsequently decomposed as, for instance, in the operation of coagulating the rotein.

The present invention is base upon the observation that tempering agents which are not soluble in or emulsifiable with a solution? of the colloid or in the medium in which the colloid is dispersed can by mechanical means he brought to the desired degree of dispersion through the coating composition.

Application filed November 21, 1923. Serial No. 676,178.

that which is regarded as characteristic of the division of the disperse phase in colloidal solutions.

As indicative of the treatment necessary, it vmay be remarked that the organic colloid disperse and the tempering agent may be passed together between surfaces spaced apart about 0.007 of an inch and moving relatively to one another at 'the rate of -17,000 to 18,000 feet per minute.

Thus, in order to secure the desired degree of dispersion a device comprising discs, the,faces of which are spaced 0.007 inches apart, fourteen inches in diameter and rotated relativel to one. another at a speed of 5,000 revo utions per minute, may be employed.

The immediateefi'ectto be secured is similar to that secured in homogenizing milk, the ultimate result being similar also.

While in accordance with they present inthe tempering agent may be secured purely by mechanical means or mechanical treatment and the employment of stablizing agents, dispersators ,and emulsifying agents entirely dispensed with, such aids to securing the desired degree of dispersion o; the-tempering agents maybe made use 0 Y Thus, for instance, pigments or other solids may be employed as ancillary dispersion means 'or stablizers.

Inorganic materials capable of forming with the dispersion medium for the colloid, colloidsols or colloidal solutions or absorbing many times their weight ofthe disperse medium forming gels, may conveniently be employed and as examples of such materials hi hly colloidal clays may be specified. Suc materials of the. char- I appear to be most suitable when, for instance, the disperse medium is water.

The material known as bentonite, de-

posits of which occur in the State of \Vyom-v ing, United States of' America, ancLin Alberta, Canada, is an example.

This material, dried at 110 0., has the following chemical composition Silica (SiO 57.98% Ferrous oxide (Fe'O) 0.12% Ferric oxide (Fe, O 3.80% Alumina (A1 0 22.46% Lime (CaO) 1.92% Magnesia (MgO) 3.24% Soda and potash Na O and K. ,O) 1.35% Sulphur trioxide (S0 0.75%

Loss on ignition (H 0, 00 Org)- 7.93%

The state of division of the material is indicated by the fact that 73.82% of the product as marketed is represented by particles less than 0.0015 mm. in diameter.

The addition of such materials may assist in securing or maintaining the tempering agent in the desired degree of dispersion, but it wouldappear that their main function is to prevent the tempering agent sweating out of the coating composition.

As an example of a suitable composition, the following may be given -150 parts by weight of a 10% solution of gelatine;

100 parts 0.85-0.90.

Tothe mixture 5 parts of bentonite previously allowed to swell or gelatinize in at least 50 parts by weight of water may be added.

Yoshino paperis coated with the composition in the usual manner and, after drying, the coated sheet may be treated with formaldehyde Vapour'if a coagulable protein constitutes the gelatinizing organic colloid in the composition.

When, however, seaweed jellies, such as agar-agar, carragheen moss, Irish moss, Iceland moss, Japanese isinglass or the like colloidal materials are employed, treatment by weight of mineral oil of s. g.

with formaldehyde vapour may be omitted.-

Claims use in duplicating manuscript and typewritten documents, drawings and the like, and particularly stencils of the kind in which a porous support, such asv yoshino paper, is provided with a stencil layer including a gelatinized organic colloid, for instance a coagulated protein, which does not need moistening in order to soften the coating composition prior to cutting the stencil, which comprises effecting by mechanical means the dispersion in the coating composition to the desired degree of tempering agents which are not soluble in the medium in which the colloid is dispersed and applying said composition to a porous support.

2. The process of producing stencils for use in duplicating manuscript and typewrit ten documents, drawings andthe like, and

'particularly stencils of the kind in which a porous support, such as yoshino paper, is

.jecting the mixture to purely mechanical treatment to bring the tempering agent to the desired degree of dispersion through the organic colloid disperse, and applying said composition to a porous support.

3. The process of producing stencils for use in duplicating manuscript and typewritten documents, drawings and the like, and particularly stencils of the kind in which a porous support, such as yoshino paper, is provided with a stencil layer including a gelatinized organic colloid, for instance a coagulated protein, which does not need moistening in order to soften the coating composition prior to cutting the stencil, which comprises bringing a disperse system including an organic colloid capable of forming a coherent gel to other with a tempering agent insoluble in t e medium in which the organic colloid is dispersed, sub jecting the mixture to purely mechanical treatment of a character to secure that the degree of dispersion ofthe tempering agent in the composition used in .formin the stencil layer is substantially that whlch isregarded as characteristic of the division of the disperse phase in colloidal solutions, and applying said composition to a porous support.

4. The process of producing stencils for use in duplicating manuscript and typewritten. documents, drawings and the like, and particularly stencils of the kind in .which a porous support, such as yoshino 1. The process of producing stenclls for' paper, is provided with a stencil layer including a gelatinized organic colloid, for instance a coagulated protein, which does not need moistening in order to soften the coating composition rior to cutting the stencil, which comprlses bringing a disperse system includlng' an organic colloid capable of forming a coherent gel together with a tempering agent insoluble in the medium in which the organic colloid is dispersed and an inorganic material canable of forming with the dispersion medium for the colloid colloid sols, subjecting the mixture to purely mechanical treatment to bring the tempering agent to the desired degree of dispersion through the organic colloid disperse, and applying said composition to a porous support.

5. The process of producing stencils for use in duplicating manuscript and typewritten documents, drawings and the like, and particularly stencils of the kind in which. a porous support, such as yoshino paper, is provided wlth a stencil layer including a gelatinized organic colloid, for instance a coagulated protein, which does not need moistening in order to soften the coating composition prior to cutting the stencil, which comprlses bringing a dis perse system including an organic colloid capable of forming a coherent gel together with a tempering agent insoluble in the medium inwhich the organic colloid is dispersed and an inorganic material capable of absorbing vmany times its weight of the disperse medium forming gels, subjecting the mixture to purely mechanical treatment to bring the tempering agent to the desired degree of dispersion through the organic colloid disperse, and applying said composition to a porous support.

6. The process of producing stencils for use in duplicating manuscript and typewritten documents, drawings and the like, and particularly stencils of the kind in which a porous support, such as yoshino paper, is provided with a stencil layer including a gelatinized organic COllOld, for instance a coagulated protein, which does not need moistening in order to soften the coating composition prior to cutting the stencil, which comprises bringing a disperse system including an organic colloid capable of forming a coherent el together with a tempering agent insolu le in the medium in which the organic colloid is dispersed and highly colloidal clays, and applying said composition to a porous support.

7. The process of producing stencils for use in duplicating manuscript and typewritten documents, drawings and the like, and particularly stencils of the kind in which a porous support, such as yoshino paper, is provided with stencil layer including a gelatinized organic colloid, for instance a coagulated protein, which does not need moistening in order to soften the coating composition prior to cutting the stencil, which comprises bringing a disperse system including an organic colloid capable of forming a coherent gel together with a tempering agent insoluble in the medium in which the organic colloid is dispersed and bentonite,

and applying said composition to a porous support.

In testimony whereof I have signed my name to this specification.

ARMAND DE WAELE. 

